SpringMVC的返回值类型和参数传递
1、SpringMVC的返回值类型
(1)ModelAndView返回值类型:
1.1当返回为null时,页面不跳转。
1.2当返回值没有指定视图名时,默认使用请求名作为视图名进行跳转。
1.3当返回值指定了视图名,程序会按照视图名跳转。
/*添加*/
@RequestMapping("/getSale")
public ModelAndView addSale(Sale sale,HttpServletRequest request,ModelAndView mv){
if (sale!=null) {
Double totalPrice = sale.getPrice() * sale.getQuantity();
sale.setTotalPrice(totalPrice);
sale.setSaleDate(new Date());
Users user = (Users) request.getSession().getAttribute("user");
sale.setUserId(user.getUid());
int i = userService.addSale(sale);
if (i > 0) {
mv.setViewName("saleList");
} else {
mv.setViewName("prodectAdd");
}
}
return mv;
}
(2)Object返回值类型:
/*绑定下拉框*/
@RequestMapping("/prodectName")
@ResponseBody
public Object getprodectName(){
List<Product> products = userService.getproductName();
return products;
}
(3)String返回值类型:
3.1如果返回值为null,那么以请求名作为视图名进行跳转;
3.2如果指定返回值,那么按照指定返回值作为视图名进行跳转,可以通过model,modeMap携带数据。
3.3如果返回值带有forward或者redirect前缀,那么将会进行相应的请求或重定向,不过不能通过mvc的数据模型携带数据,可以通过ServletApi携带数据。
@RequestMapping("/welcome")
public String welcome(String userName, Model model){
//将用户名保存到对应的作用域中
model.addAttribute("userName",userName);
return "welcome";
}
2.参数传递
(1)JSP页面(注意点*:控制器Controller中的方法参数名称必须和表单元素的name属性值保持一致)
<form class="loginForm" action="/user/getUser" method="post" >
<div class="inputbox" style="text-align:center; ">
<label for="user">用户名:</label>
<input id="user" type="text" name="userName" placeholder="请输入用户名" />
</div>
<div class="password" style="text-align:center; " >
<label for="mima">密码:</label>
<input id="mima" type="password" name="password" placeholder="请输入密码" />
</div>
<div class="subBtn" style="text-align:center; ">
<input type="submit" value="登录" />
<input type="reset" value="重置"/>
</div>
</form>
/*登录*/
@RequestMapping("/getUser")
@ResponseBody
private ModelAndView getUser(String userName, String password, ModelAndView mv, HttpServletRequest request, HttpServletResponse response, HttpSession session){
Users user = userService.getUser(userName,password);
System.out.println("user======"+user);
if (user!=null){
System.out.println("成功");
//登录成功
request.getSession().setAttribute("user",user);
//转发
mv.setViewName("index");
}else{
//登录失败
mv.setViewName("login");
}
return mv;
}
(2)请求参数装配为POJO对象
新增Person
public class Person {
private String username;
private int age;
//省略get/set方法
}
控制器
//当实体类中的属性名和表单元素的name属性相同时,即可完成自动装配
@RequestMapping(value = "personObject",method = RequestMethod.POST)
public String personObject(Person person){
System.out.println(person);
return "hello";
}
(3)@RequestParam注解
@RequestParam的作用是,当表单元素与控制器方法的参数不匹配的情况下,使用@RequestParam注解声明参数名称。
@RequestParam 有三个属性:
3.1value:请求参数名(必须配置)
3.2required:是否必需,默认为 true,即 请求中必须包含该参数,如果没有包含,将会抛出异常(可选配置)
3.3defaultValue:默认值,如果设置了该值,required 将自动设为 false,无论你是否配置了required,配置了什么值,都是 false(可选配置)
jsp页面
<form class="loginForm" action="/getUser" method="post" onsubmit="return check()" >
<div class="inputbox" style="text-align:center; ">
<label for="user">用户名:</label>
<input id="user" type="text" name="userName" placeholder="请输入用户名" />
</div>
<div class="password" style="text-align:center; " >
<label for="mima">密码:</label>
<input id="mima" type="password" name="password" placeholder="请输入密码" />
</div>
<div class="subBtn" style="text-align:center; ">
<input type="submit" value="登录" />
<input type="reset" value="重置"/>
</div>
</form>
控制器
<form class="loginForm" action="/getUser" method="post" onsubmit="return check()" >
<div class="inputbox" style="text-align:center; ">
<label for="user">用户名:</label>
<input id="user" type="text" name="userName" placeholder="请输入用户名" />
</div>
<div class="password" style="text-align:center; " >
<label for="mima">密码:</label>
<input id="mima" type="password" name="password" placeholder="请输入密码" />
</div>
<div class="subBtn" style="text-align:center; ">
<input type="submit" value="登录" />
<input type="reset" value="重置"/>
</div>
</form>
(4)RESTFUL风格的参数传递
/*{id}表示占位符*/
@RequestMapping("/getid/{id}")
@ResponseBody
public Object getid(@PathVariable("id") Integer id){
List<Accounts> name = accountService.getName(id);
return name;
}
(5)对象传递参数
IUserInfo实体类:
package com.cmy.entity;
import java.util.ArrayList;
import java.util.List;
public class IUserInfo {
private int uid;
private String username;
//域属性注入
private Teacher teacher;
private List<Teacher> teacherList;
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public int getUid() {
return uid;
}
public void setUid(int uid) {
this.uid = uid;
}
public Teacher getTeacher() {
return teacher;
}
public void setTeacher(Teacher teacher) {
this.teacher = teacher;
}
public List<Teacher> getTeacherList() {
return teacherList;
}
public void setTeacherList(List<Teacher> teacherList) {
this.teacherList = teacherList;
}
@Override
public String toString() {
return "IUserInfo{" +
"uid=" + uid +
", username='" + username + '\'' +
", teacher=" + teacher +
", teacherList=" + teacherList +
'}';
}
}
控制层
@Controller
@RequestMapping("/fout")
public class FoutController {//属性
@RequestMapping("/getUser")
public String getUser(IUserInfo userInfo){
System.out.println(userInfo.toString());
return "welcome";
}
}
页面
域属性1
<form class="loginForm" action="/fout/getUser" method="post" onsubmit="return check()" >
<div class="inputbox" style="text-align:center; ">
<label for="user">用户名:</label>
<input id="user" type="text" name="teacher.teachername" placeholder="请输入用户名" />
<input id="users" type="text" name="teacher.teachername" placeholder="请输入用户名" />
</div>
<div class="password" style="text-align:center; " >
<label for="mima">密码:</label>
<input id="mima" type="password" name="password" placeholder="请输入密码" />
</div>
<div class="subBtn" style="text-align:center; ">
<input type="submit" value="登录" />
<input type="reset" value="重置"/>
</div>
</form>
集合2
<form class="loginForm" action="/fout/getUser" method="post" onsubmit="return check()" >
<div class="inputbox" style="text-align:center; ">
<label for="user">用户名:</label>
<input id="user" type="text" name="teacherList[0].teachername" placeholder="请输入用户名" />
<input id="users" type="text" name="teacherList[1].teachername" placeholder="请输入用户名" />
</div>
<div class="password" style="text-align:center; " >
<label for="mima">密码:</label>
<input id="mima" type="password" name="password" placeholder="请输入密码" /></div>
<div class="subBtn" style="text-align:center; ">
<input type="submit" value="登录" />
<input type="reset" value="重置"/>
</div>
</form>